JPH0726587Y2 - Shock absorber - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a shock absorber that absorbs kinetic energy of a load member.

[Conventional technology and its problems]

Conventionally, a shock absorber for absorbing kinetic energy is often used in a stop device for stopping a kinetic load such as a pallet conveyed on a conveyor at a fixed position.

When the moving load member hits the tip of the piston rod, the shock absorber, for example, a piston connected to the piston rod slides in the backward direction in an airtight manner on the inner peripheral surface of the main body tube whose end surface is closed by the end cover. , Is configured to absorb shock by compressing trapped air. The compressed air is released to the atmosphere via a throttle valve or a relief valve, and the cushion effect is adjusted by adjusting the throttle amount or the set pressure.

Then, after the load member is removed, the piston and the piston rod are automatically returned to their original positions by the return spring.

However, if the load member is only an inertial load or the position holding force of the load member due to friction etc. is weak, the load member returns to its original position together with the piston and piston rod after the stop and is pushed back. Therefore, there is a problem in that the stop position of the load member is displaced and the load member (for example, pallet) cannot be positioned.

On the other hand, without using a return spring as the return means, the return is made by the pressure of the compressed air, and
An air return type shock absorber has been proposed in which the timing of supplying compressed air for recovery is controlled by an electromagnetic switching valve.

However, according to this, an electric signal is required to obtain the switching timing of the electromagnetic switching valve, the control becomes complicated, and the shock absorber is a hydraulic type and for converting return air pressure to hydraulic pressure. When using an oil tank, there is a problem that a large space for the oil tank is required and that compressed air easily mixes with the oil.

In view of the above-mentioned problems, the present invention aims to provide a shock absorber having a simple structure in which the load member is not pushed back by a return spring or the like after stopping, and the position of the load member does not shift after stopping. I am trying.

[Means for Solving the Problems]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention absorbs an impact by moving a piston connected to a piston rod in a backward direction, and a shock configured to return the piston and the piston rod by a returning means. In the absorber, a return suppression cylinder is provided at the tip of the piston rod at a position where the load member is pressed, and the recovery suppression cylinder is a suppression piston engaged with the piston rod at least in the backward direction. A restraining piston rod that moves integrally with the restraining piston and a load member contacts the tip of the restraining piston; and a side of the restraining piston rod for pressing the restraining piston in the backward direction with a force stronger than the restoring force of the piston rod. And an air chamber connected to the air chamber for supplying compressed air to the air chamber. A port provided so that the compressed air in the air chamber is exhausted from the opening at the tip of the restraining piston rod, and a load member presses against the tip of the restraining piston rod. And a sealing member for cooperating with the load member to close the opening.

[Action]

When the load member pushes against the tip of the restraint piston rod, the restraint piston rod, restraint piston, and piston rod move in the backward direction due to the kinetic energy of the load member, exerting a buffering action, and the stroke end of the piston (the backward direction (The moving end of) and stop.

While the load member is pressing against the tip of the suppression piston rod, the opening of the exhaust flow path is blocked by the load member and the seal member, the air pressure in the air chamber rises, and the piston rod is pressed by the thrust of the suppression piston. To be As a result, the piston and the piston rod are restrained from returning by the returning means and hold their positions.

When the load member is removed, the opening is released and the compressed air in the air chamber is discharged from the exhaust flow path and the opening, the pressure in the air chamber is reduced and the thrust of the suppression piston is reduced, and the piston and piston rod are Restored by the restoring means.

〔Example〕

 Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a sectional front view of a shock absorber 1 according to the present invention.

The shock absorber 1 is composed of an absorber main body 2 having a screw 3 formed on the outer peripheral surface thereof, and a return suppressing cylinder 5 attached to the tip end side of the absorber main body 2 at a position where a load member is pressed. .

The absorber body 2 absorbs the shock by the piston (not shown) connected to the piston rod 7 moving in the backward direction (the direction of arrow A in the figure), and the piston and the piston rod 7 are returned by a return means such as a return spring (not shown). Is known in the art.

The recovery suppressing cylinder 5 includes a cylinder tube 11 having a screw 12 formed on an inner peripheral surface thereof, a suppressing piston 13 slidingly moving on the inner peripheral surface of the cylinder tube 11 and abutting against a tip surface 7a of a piston rod 7, and a suppressing piston. Suppressing piston rod 14 formed integrally with 13 and having a load member abutting on its tip surface 14a
It consists of

The cylinder tube 11 is provided with a port 16 and a throttle passage 17 for supplying compressed air to the air chamber 15 on the side of the suppression piston rod 14, and the chamber 18 on the side of the piston rod 7 is provided.
A through hole 19 is provided in the.

The suppression piston rod 14 is formed with an exhaust flow path 20 for exhausting the compressed air in the air chamber 15 from an opening 21 that opens at the tip surface 14a, and the opening 21 has a load member W.
A packing 22 for closing the opening 21 in a hermetically closed state when pressed against is attached. In addition, 4 is a mounting nut, and 23 and 24 are packings.

Next, the operation of the shock absorber 1 configured as described above will be described.

An air pressure source of appropriate pressure is connected to port 16,
The compressed air supplied from there flows into the air chamber 15 through the throttle channel 17, and is discharged from the opening 21 through the exhaust channel 20 when the load member W is not pressed against the tip surface 14a. . The inflow of compressed air into the air chamber 15 is throttled by the throttle passage 17, and the outflow from the air chamber 15 is exhausted without resistance by the exhaust passage 20, so that the air pressure of the air chamber 15 is substantially zero, Almost no thrust is generated in the suppression piston 13.

When the load member W presses against the tip 14a of the restraining piston rod 14 (state shown by a chain line), the restraining piston rod 14, the restraining piston 13, and the piston rod 7 move in the backward direction by the kinetic energy of the load member W, The absorber main body 2 exerts a cushioning effect, and reaches the stroke end (moving end in the backward direction) and stops.

While the load member W is pressed against the tip surface 14a of the suppression piston rod 14, the opening 21 is sealed by the load member W and the packing 22, so that the air pressure in the air chamber 15 rises and the suppression piston 13 moves. The thrust pushes the piston rod 7 in the backward direction. As a result, the absorber body 2
Is restrained from returning by the return spring and holds the position of the stroke end.

When the load member W is removed, the opening 21 is released, the compressed air in the air chamber 15 is discharged from the exhaust passage 20 and the opening 21, and the pressure of the air chamber 15 is reduced so that the thrust of the suppressing piston 13 is increased. Then, the piston rod 7 of the absorber body 2 is returned by its return spring.

According to the above-described embodiment, the opening 21 acts as a sensor for controlling the air pressure of the air chamber 15, and the load member W is applied to the opening 21.
Since the pressure of the air chamber 15 rises and suppresses the return of the absorber main body 2 while the load member W is pressed or abutted, it is not pushed back by the return spring of the absorber main body 2 after the load member W is stopped, The position of the member W after stopping does not shift. Moreover, the structure is simple and no special control is required.

In the above-described embodiment, the shock absorber 1 may be attached to the moving side (load member side), and the fixed side may be attached with a stopper for the tip 14a of the restraining piston rod 14 to abut.

In the above-described embodiment, the area of the air chamber 15 and the pressure of the compressed air supplied to the port 16 can be appropriately determined according to the restoring force of the restoring means of the absorber body 2. Packing
A gasket may be used instead of 22, or the packing 22 may be omitted and sealing may be performed by the front end surface 14a. The shape and structure of each part of the recovery restraint cylinder 5, the method of attaching the recovery restraint cylinder 5 to the absorber body 2, the method and structure of the absorber body 2, and the like can employ various other things.

[Effect of device]

According to the present invention, the load member is not pushed back by the returning means after the load member is stopped, and the position of the load member after the stop is not displaced. Moreover, the structure is simple and no special control is required.

[Brief description of drawings]

FIG. 1 is a sectional front view of a shock absorber according to the present invention. 1 ... Shock absorber, 5 ... Return suppression cylinder,
7 ... Piston rod, 13 ... Suppression piston, 14 ... Suppression piston rod, 14a ... Tip surface (tip), 15 ... Air chamber, 20 ... Exhaust flow passage, 21 ... Opening part, 22 ... Packing (seal member), W ... Load member.

Claims (1)

[Scope of utility model registration request] Claim: What is claimed is: 1. A shock absorber, wherein a piston connected to a piston rod moves in a backward direction to absorb a shock and at the same time, the returning means restores the piston and the piston rod. A return suppression cylinder is provided at the tip of the load member at a position where the load member presses, and the return suppression cylinder is integrally formed with the suppression piston engaged with the piston rod at least in the backward direction, and the suppression piston. A restraining piston rod that moves and a load member contacts the tip thereof, and an air chamber provided on the restraining piston rod side to press the restraining piston in a backward direction with a force stronger than the restoring force of the piston rod. Provided to communicate with the air chamber for supplying compressed air to the air chamber A port, an exhaust passage formed to exhaust compressed air in the air chamber from an opening at the tip of the restraining piston rod, and the load member when the load member presses against the tip of the restraining piston rod. A shock absorber, comprising: a seal member that cooperates with the seal member to close the opening.